1. Field of the Invention
The present invention relates to a torque measurement device capable of measuring a torque of a steering system.
2. Discussion of Related Art
In general, in a vehicle, a steering wheel connected to wheels is manipulated to change a driving direction. However, when a resistance between the wheels and a road surface is high or steering is interfered, a manipulation force may be decreased to make it difficult to rapidly manipulate the steering wheel, and in order to solve the problem, a power steering apparatus is used. The power steering apparatus is an apparatus for reducing manipulation power via a power device configured to assist manipulation of the steering wheel.
In order to assist the manipulation of the steering wheel via the power device, the torque applied to a steering shaft should be measured. Accordingly, various types of apparatuses are used to measure the apparatus for measuring the torque of the steering wheel. In particular, the technique of measuring a magnetic field between the steering shaft and a magnet coupled to the steering shaft to detect a torque has good economic feasibility and is widely used.
A general steering system is constituted of an input shaft to which a steering wheel is coupled, an output shaft coupled to a pinion meshed with a rack bar on a wheel side, and a torsion bar and a torque measurement device configured to connect the input shaft and the output shaft.
When the steering wheel is rotated, the rotational force is transmitted to the output shaft and the direction of the wheel is changed by an action of the pinion and the rack bar. In this case, since the input shaft is more largely rotated more when the resistance is more strongly applied, the torsion bar is twisted and the twisted level of the torsion bar is measured by a magnetic field type torque measurement device.
In recent times, research on a structure for minimizing the size of the torque measurement device while maximally suppressing a flux leakage generated therefrom is actively being performed.